DE 199 61 871 A1 discloses a driver information system detecting several operational data of a motor vehicle by means of a control unit and defining a priority in terms of the relevance of the operational data for the driver and transmitting it to the driver by means of a signal. It is considered a shortcoming in the prior art driver information system that a defect of the output unit drawing the driver's attention to critical operating conditions by way of an optical and/or audible signal is not discovered.